In general, the bigger the bird, the higher the number of feathers. Someone counted the feathers on a Tundra Swan and came up with 25,216. At least 80% were on the swan’s neck. Penguins, on the other hand, have lots of small feathers all over their bodies. The largest species is the…

Compared to many birds, Great Horned Owls remain with their parents a long time. They hatched in early March, from eggs laid in late January. By April, both parents were hunting through the night to feed their young. But for the last two weeks, the adults have not fed the young. The owlets…

American Goldfinches are one of our most familiar birds, but they lead lives that are anything but ordinary. These birds will sometimes raise two broods a year, have a secret weapon against cowbirds, and have the ability to distinguish between songs that — to our ears — sound the same…

At a glance, swallows and swifts, both graceful fliers, look much alike. But swifts — like this Chimney Swift — have longer, slimmer wings and short bodies, enabling them to glide for long periods. Their glides are punctuated by rapid, stiff bursts of wing-beats. Swallows, on the other…

Once abundant around San Francisco Bay, the Ridgway’s Rail — formerly known as the California Clapper Rail — is now endangered. In the 19th Century, unregulated hunting plundered the species. In the 20th Century, rampant development reduced salt marsh habitat by 85%. But in the 21st…

Let’s talk about nests. Every spring, robins build their cup-shaped nests using grass and mud. Orioles weave a hanging sack. It’s hard work, and yet once the chicks fledge, the structures probably won’t be reused. But bigger birds, such as herons, hawks, and eagles, often reuse a nest for…

By early August, the rich yellow of the feathers of the Wilson's Warbler seems to flash in every forest thicket. Despite predators and weather, many pairs of adults have raised four young, which now flit about on their own. The young males hatched this spring learned their father's songs…

In September, this Arctic Tern flies from Alaska all the way to Antarctica. Rufous Hummingbirds follow pathways of mountain wildflowers, from as far north as Alaska south to Mexico. Ruby-crowned Kinglets, migrate attitudinally from the mountains to the lowlands. Each of these birds…

A tern or gull plunges headfirst into the water, then bounces aloft grasping a small fish in its bill. But before the bird can swallow its catch, a Parasitic Jaeger swoops in. The jaeger nips the bird's wing, and it drops its hard-won fish. The pirate catches the fish in mid-air and gulps…

La telaraña es una obra de ingeniería de precisión. Hecha de grandes proteínas, es pegajosa, elástica y resistente. Por eso no es sorprendente que muchas aves pequeñas recolecten hebras de seda de araña para usarlas en la construcción de sus nidos. La seda de araña no solo actúa como…